Scientists chase colliding black holes

Leicester scientists have revealed today they have been involved in the search of the distant universe for the counterpart to a second Gravitational Wave source.

This week the advanced LIGO facility in the USA announced that they had detected Gravitational Waves from a merging binary black hole for the second time.

Within hours of this discovery on 26 December, scientists from our University and an international team used the Swift satellite to search for associated X-ray and ultra-violet emission.

The team found no sign of the merging stars with Swift, nor with the VISTA telescope in Chile, which performed observations 7-13 days after the trigger. This is in itself a result.

However, the large uncertainty in where the gravitational wave event occurred makes it hard to be sure whether the astronomers looked in the right place.

Later this year a second gravitational wave observing run will start, with the European advanced VIRGO facility expected to join advanced LIGO. Scientists hope for the first gravitational discovery of merging neutron stars with the resulting improved sensitivity and precision.

But will the Swift team be able to find such light, given the size of the haystack they have to search? Dr Phil Evans, who coordinates the Swift response to Gravitational Wave events, is confident that they will: "We've recently enabled a new observing mode, which will let us cover something like ten times as much sky for future events than we've been able to do so far,'' he said. "In the future we can simultaneously shrink the haystack, identify which bits are most likely to contain the needle, and search through it more rapidly."